The present invention relates generally to needle-free or needleless injection systems and more specifically to such a system that is particularly well suited for being used a single time and then being discarded.
Needle-free systems have been in use for many years. Some such systems have used a pressurized gas to power a hypodermic jet injection. The related technology includes a number of teachings for gas-powered injection devices, including: U.S. Pat. No. 4,596,556 to Morrow, et al.; U.S. Pat. No. 4,913,699 to Parsons; U.S. Pat. No. 5,730,723 to Castellano, et al.; and WIPO publication WO 97/3705 naming Weston and Thornlea as inventors.
In accordance with the current invention, a needle-free injection system includes a cap that has a first seal for sealing an injection orifice when the cap is engaged with an injection end of the system. The cap also includes a push-rod for facilitating priming of the system when engaged with a priming end of the system. The system also includes a push-rod engaging mechanism disposed at the priming end of the system for receiving the push-rod for priming the system. The system further includes a gas cylinder for supplying pressurized gas for injecting, via the injection orifice, an injectate initially disposed within a storage chamber, and a sealing system for preventing the pressurized gas from ejecting the injectate from the system prior to actuation of the stem. Actuation of the system is achieved via a slidable trigger plate. The sealing stem includes a second, radially displaceable seal initially disposed within a pressurized gas channel, and a corresponding recess in the slidable trigger plate for receiving the second seal as a result of actuation.